The invention relates to pump devices for loading fluid into a tank. In particular, the invention involves conduit devices that can load fluid onto an aircraft, either fixed wing or rotocraft, from a fluid source such as a lake, river, reservoir, or ocean while remaining airborne.
For many years, special aircraft have been designed and used to carry and deliver water to a fire. Helicopters or xe2x80x9chelitankersxe2x80x9d may be equipped with fire suppression systems that are capable of loading water from a source such as a lake or an ocean, into an onboard tank, and then transporting and dispensing the water onto a fire. Recently, the world-wide demand for helitanker fire fighting services has expanded. Helitanker fire fighting operations are now often required in areas where fresh water sources are scarce and salt water sources are abundant. Therefore, helitankers must be able to utilize sea water as a retardant without damaging aircraft components or compromising safety.
Conventional FAA approved hose or xe2x80x9csnorkelxe2x80x9d devices are unsatisfactory for use with salt water because these snorkels require the helicopter to hover at a level that results in rapid loss of power due to salt accumulation in the engines. For example, U.S. Pat. No. 3,897,829 discloses a helicopter equipped with a suction conduit that is designed to hang vertically below a hovering helicopter to load water from a source into an onboard tank. A significant problem with this type of water suctioning device is that downwash generated by the rotor causes water from the source to splash onto the underside of the helicopter. This can be a serious problem when the source contains salt water because the salt may cause parts of the helicopter to rust and corrode. Salt spray ingested into the engines can cause internal damage and result in a loss of power and eventually may cause total failure of one or both engines. Another problem with use of dangling hoses in ocean water is that the hose may bounce in and out of the water if the ocean is wavy or turbulent.
Accordingly, an object of the invention is to provide a system for loading fluid onto an aircraft from a salt water source without ingesting fluid into the aircraft engines.
Another object of the invention is to provide a conduit device for loading fluid into a tank on board an aircraft, in which the conduit device can remain partially stabily submerged in the fluid source while the aircraft flies over the source at a ground speed sufficient to stay ahead of the spray generated by the rotor wash.
Another object of the invention is to provide a fluid loading system that may be versatily employed to load fluid from different types of sources, for example, oceans, lakes, rivers, and reservoirs, in varying shapes, depths, and degrees of salinity.
The invention provides a fluid loading and transport system for an aircraft. A substantially rigid tube member is connected to the aircraft in communication with the tank. The tube member is movable into a downward orientation for accessing a fluid source while the aircraft flies over the source and may be retracted in times of non-use.
One aspect of the invention relates to a fluid conduit device having a distal end equipped with a diving device, preferably in the form of an inverted hydrofoil, that substantially maintains the distal end of the conduit device below a surface of the water source while the aircraft flies over the water source.
Another aspect of the invention provides a fluid conduit device in which a tube member has a strut running along at least a portion of the length of the tube member. The strut is configured to stabilize a submerged distal end of the tube member while the aircraft moves over a fluid source.
Still another aspect of the invention involves a fluid conduit device in which a tube member is connected to an aircraft in communication with an onboard tank so that the tube member maintains a substantially rearward angular orientation when the aircraft translates over the fluid source and the distal end of the tube member is submerged.
The invention also provides a method of loading water onto a moving aircraft. Fluid is transferred from a source through a tube member into a tank on an aircraft by a pump or ram pressure generated by the forward velocity of the aircraft as it moves over the source. In a preferred procedure, the tube member is directed rearward relative to the aircraft""s direction of travel. A distal portion of the tube member is maintained below the surface of the fluid source by providing a diving device near the distal portion.